1. Field of the Invention
The present invention relates generally to Wireless Communication Devices (WCDs), and more particularly, to such a Wireless Communication Device capable of operating with different types of communication networks.
2. Background Art
As mobile communication systems become more prevalent in society, the demands for greater and more sophisticated service have grown. To meet the capacity needs of mobile communication systems, techniques of multiple access to a limited communication resource have been developed. The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA) and frequency division multiple access (FDMA) are known in the art. However, the spread spectrum modulation technique of CDMA has significant advantages over these modulation techniques for multiple access communication systems.
The use of CDMA techniques in a multiple access communication system is known in the art and is disclosed in U.S. Pat. No. 4,901,307, issued Feb. 13, 1990, entitled xe2x80x9cSPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,xe2x80x9d assigned to the assignee of the present invention. The use of CDMA techniques in a multiple access communication system is further disclosed in U.S. Pat. No. 5,103,459, issued Apr. 7, 1992, entitled xe2x80x9cSYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM,xe2x80x9d also assigned to the assignee of the present invention.
Presently, there are many different types of communication networks offering services to users. Some types of communication networks are optimized for providing both voice and relatively slow data-rate data services to a user. Such communication networks include networks operating in accordance with International Standard (IS) 2000 (that is, IS-2000) or the Global System for Mobile (GSM) Communications standards, for example. On the other hand, other types of communication networks are optimized for providing efficient, relatively high-speed packet data services to the user. Such communication networks include High Data Rate (HDR) networks operating in accordance with IS-856 communication standards, for example.
The user typically accesses voice and/or data services associated with the different types of communication networks using a mobile terminal (referred to herein as a Wireless Communication Device (WCD)). However, conventional WCDs are typically capable of operating over only one type of communication network, such as with an IS-2000 network system, or alternatively, with an IS-856 network system. Therefore, such conventional WCDs do not individually provide optimized communication services to the user for both types of communication networks. As a result, the user may need to use multiple, different WCDs should the user wish to utilize the optimized services available on the different networks.
Therefore, there is a need for a WCD capable of operating over the above-mentioned different types of networks, thereby providing a user of the WCD with optimized voice and data services associated with the different types of networks.
A portable WCD is typically capable of operating on battery power. It is desirable for such a battery powered WCD to have as long a battery lifetime as possible. In the past, much effort has been expended to minimize WCD power dissipation, thereby extending the WCD battery lifetime. Therefore, in addition to the above-mentioned need to operate a single WCD on different types of networks, there is a related need to operate the WCD in a power efficient manner aimed at conserving battery power, and thus extending the WCD battery lifetime.
The present invention is directed to a hybrid access terminal (also referred to as a WCD) capable of operating over different types of communication networks, and a method of operating the WCD on the different types of networks. An exemplary WCD of the present invention operates on both IS-2000 and IS-856 networks, and is capable of inter-system handoffs between these two types of networks. Such capabilities enable the exemplary WCD to provide voice, data and short messaging services on IS-2000 networks, and also to provide high speed packet data service on IS-856 networks. By supporting services on both types of networks, the WCD enables the user of the WCD to realize the best possible services for voice, data and short messaging, while also enabling network operators to realize the network capacity benefits that are achievable by overlaying IS-2000 and IS-856 systems, each of which is optimized for the type of services provided. The primary design drivers for the above-mentioned inter-system operation of the hybrid WCD include the following:
Support IS-2000 voice services and mobile directed short messaging services at any time, minimize call setup time, maximize network capacity, and maximize mobile standby time by conserving battery power.
The WCD of the present invention is capable of establishing data sessions on both a first network (such as an IS-2000 network) supporting voice and data services, and a second network (such as an IS-856 network) supporting packet data services. According to a method of the present invention, the WCD acquires the first network, and monitors a paging channel of the first network. Next, the WCD establishes a data session on the first network. Next, the WCD detects a request for a packet data service.
In response to detecting the request, the WCD hands-off the data session from the first network to the second network, thereby establishing the data session on the second network. Once the data session is established on the second network, the WCD detects a dormancy of the data session corresponding to a predetermined period of time during which data is not being exchanged between the WCD and the second network. The WCD initiates a Dual System Dormancy Timer in response to detecting the dormancy. The WCD monitors both a paging channel of the first network and a paging channel of the second network in response to detecting the dormancy. Then, the WCD monitors only the first network paging channel when the dormancy-timer expires.
According to an aspect of the present invention, the WCD comprises means for establishing the data session on the first network and means for detecting the request for the packet data service (PDS). The WCD also includes means for handing-off the data session from the first network to the second network when the PDS request is detected. The WCD also includes means for detecting the dormancy of the data session corresponding to the predetermined period of time that data is not being exchanged between the WCD and the second network. The WCD also includes a Dormancy Timer, and means for initiating the Dormancy Timer in response to detecting the dormancy. The WCD further includes means for monitoring both the paging channel of the first network and the paging channel of the second network in response to detecting the dormancy. The WCD also includes means, responsive to the Dormancy Timer, for monitoring only the first network paging channel when the Dormancy Timer expires.
Another aspect of the present invention is a computer program product comprising a computer usable medium having control logic stored therein for causing a processor of the WCD to control the WCD, such that the WCD is capable of establishing data sessions on both the first network supporting voice and data services and the second network supporting packet data services. The control logic comprises first computer readable program code means for causing the processor to establish the data session on the second network, second computer readable program code means for causing the processor to detect the dormancy of the data session corresponding to the predetermined period of time that data is not being exchanged between the WCD and the second network, third computer readable program code means for causing the processor to initiate the Dormancy time-out period when the dormancy is detected, fourth computer readable program code means for causing the processor to monitor both the paging channel of the first network and the paging channel of the second network when the dormancy is detected, and fifth computer readable program code means for causing the processor to monitor only the first network paging channel when the Dormancy time-out period expires.
Terms and Definitions
Dormant modexe2x80x94a data session is active but no air-link resources are assigned.
Hybrid access terminalxe2x80x94an access terminal capable of providing service on first and second different types of networks, such as IS-2000 and IS-856 networks.
HDRxe2x80x94High Data Rate wireless packet data service technology.
IS-2000xe2x80x94standard for spread spectrum communication systems.
IS-856xe2x80x94standard for high speed spread spectrum packet data systems; also refers to HDR.
PDSNxe2x80x94packet data serving node.
Slotted operationxe2x80x94WCD idle state operation that enables improved power conservation.
Radio Access Network (RAN)xe2x80x94the first or second network over which the WCD can communicate, such as an IS-2000 network or an IS-856 network, for example.
Unicast Access Terminal Identifier (UATI)xe2x80x94the UATI is a unique number that is assigned to the WCD by a network (such as an IS-856 network system) upon the establishment of a new session between the network and the WCD, to identify the WCD over the course of the session.
Data Rate Control (DRC) channelxe2x80x94a reverse-link physical channel defined as part of the IS-856 physical layer and used by the WCD to indicate to the network (for example, an IS-856 network system) a maximum data rate the WCD is able to receive at any instant in time.